WP AER48 Air to Spring Conversion Kit (ATS)
WP AER48 Air to Spring Conversion Kit (ATS)
WP AER48 Air to Spring Conversion Kit (ATS)

WP AER48 Air to Spring Conversion Kit (ATS)

Regular price $645.00
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Spring Rate

The KTM and Husqvarna  WP48 Air to spring conversion kit is aimed to suit all the range of KTM's and Husqvarna that come equipped with the WP48 AER fork as standard.  This includes Ktm's SXF, SX ,XC and XCF models as well as Husqvarna's equivalent bikes in the FC, TC,TX and FX range. 

If its got WP AER48 forks in your bike as OEM equipment , this kit will fit. No need to ever set air pressure again, transforming front end feel, corner entry and less pressure / spring rate variables whilst riding over long distance.

Spring Preload adjustable via a 22mm hex on top without any disassembly

Install Video:


Our WP Air to spring conversion kit is a complete replacement cartridge assembly for your current WP AER setup.  It is designed to completely remove all the Air system from your current WP AER 48 fork  and replace it with a preload adjustable spring and cartridge setup.  High Quality German Engineered ‘Eibach’ Springs are available to suit varying rider weights.  Please advise upon order which spring you require (see recommendations below) or let us know your weight and speed  and we will recommend the best spring for you. 

This kit fit's in minutes.  If you can pull down and service your fork seals on the WP AER 48 fork you can install this kit. Info and instruction included.

Spring Rate Recommendation 

 250F and 2 Strokes 

KG LBS Recommended Spring Rate  Pro or A grade 
 <60kg <130 0.80 kg/mm 0.84kg/mm
60-65kg 130 -140 0.84kg/mm 0.88kg/mm
65-75kg 140-165 0.88kg/mm 0.92kg/mm
75-85kg 165-185 0.92kg/mm 0.96kg/mm
85-95kg 185-205 0.96kg/mm 1.00kg/mm
95-100kg 205-220 1.00kg/mm 1.04kg/mm
100-110kg 220-240 1.04kg/mm 1.08kg/mm
110kg+ 240+ 1.08kg/mm 1.08kg/mm



KG LBS Recommended Spring Rate  Pro or A grade 
 <60kg <130 0.84 kg/mm 0.84kg/mm
60-65kg 130 -140 0.88kg/mm 0.88kg/mm
65-75kg 140-165 0.92kg/mm 0.96kg/mm
75-85kg 165-185 0.96kg/mm 0.98kg/mm
85-95kg 185-205 0.10kg/mm 1.04kg/mm
95-100kg 205-220 1.04kg/mm 1.04kg/mm
100-110kg 220-240 1.04kg/mm 1.08kg/mm
110kg+ 240+ 1.08kg/mm 1.08kg/mm

General riding & Motocross applications

These recommendations  are a guide only as fork Springs are weight and speed dependent. For example a 72 kg Pro rider falls into the 0.88kg/mm category but may well be better suited to a 0.92kg spring due to the much higher corner entry speed and the ability to hit large bumps at high speeds. Please note this guide is for rider weight ‘without’ gear.

Please note we have had great results using one spring down for Veteran/ C level riders on the 450 machines.  Eg. 90kg rider running a 0.96kg/mm spring for a plusher ride.

For more accurate advice please consult your local suspension tech or send us an email.

 Rider weight Spring Recommendation ( Pro Level riders may consider one rate harder than recommended due to the faster speed and need for 'hold up')

Key Features

  • Never have to set your air pressure ever again.
  • Much more reliable fork
  • Super smooth action resulting from our tested spring guidance system. 
  • Hydraulic Bottoming resistance using our tapered bottoming piston and seat.
  • No Fade out or pump up in pressure over long moto’s
  • A Constant feel in your front end that  is more consistent throughout the ride
  • Spring Pre load adjustable minimal tools are required for fitment. If you have the Fork cap and basic tools to remove the standard OEM Air cartridge you will have the ability to fit up our kit.  Our cartridge kit is made from High grade 6061 Aircraft Grade Alloy , Chrome Moly rods and Anodised for a Factory Finish. Instruction manual included.


Parts included in the kit

  • Fully Complete Cartridge assembly including Bottoming Cone and preload washers 
  • Optional Selected Eibach spring to suit this kit



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